Effects of a 6-Week Treadmill Training With and Without Virtual Reality on Frailty in People With Multiple Sclerosis

Objective: To examine the effects of a cognitive-motor rehabilitation program consisting of treadmill training (TT) augmented by virtual reality (TT+VR) on frailty in people with multiple sclerosis (pwMS). Design: Secondary analysis from a multicenter randomized controlled trial investigating the effects of TT+VR, compared with TT only, on measures of mobility and cognitive function in pwMS. Setting: Four university research laboratories in 3 countries. Participants: A total of 124 pwMS were randomized into the parent trial. Here, we studied a subset of n = 83 participants (mean age, 49.4±9.3y; 73.5% female; expanded disability status scale range, 2.0-6.0), who completed the intervention and had complete preintervention and postintervention frailty data. Interventions: Participants were randomly allocated to TT+VR (n=44) or TT (n=39). Both groups trained 3 times a week for 6 weeks. Main Outcome Measures: Frailty was assessed using a 40-item frailty index (FI) through standard validated procedures and represented the primary study outcome. Two exploratory frailty indices were also computed by isolating health-related deficits involving the cognitive (FI-physical) or physical (FI-cognitive) domains from the main FI. The assessments were performed at baseline and after 6 weeks, upon intervention completion. Results: The mean FI of study participants at baseline was 0.33±0.13, indicating a moderate average level of frailty. FI scores improved in both TT+VR and TT groups participants (pooled mean ΔFI, 0.024; 95% CI, 0.010-0.038; F=10.49; P=.002; η_p²=0.115), without any group-by-time interaction (F=0.82; P=.367; η_p²=0.010). However, a significant group-by-time interaction was found for pretraining and posttraining changes in FI-cognitive (F=5.74; P=.019; η_p²=0.066), suggesting a greater improvement for TT+VR group participants than for TT group participants. Conclusions: TT with or without virtual reality can reduce frailty levels in pwMS. While both TT and TT+VR had a positive effect on overall frailty, only TT+VR improved cognitive aspects of frailty and may represent an appropriate strategy for counteracting frailty in pwMS.